(a) Field of the Invention
This invention generally relates to a valve system for allowing intake and exhaust of combustion gasses for an internal combustion engine. More particularly, but not by way of limitation, to an axial valve system that rotates along an axis to allow the introduction and release of gasses from a combustion chamber.
(b) Discussion of Known Art
Axially rotating valve systems for internal combustion engines have been known for some time. Examples of these systems or devices are listed below:
U.S. Pat. No.InventorDate of Issue6,443,110QattanSep. 3, 20025,249,553GuiodOct. 5, 19934,944,261CoatesJul. 31, 19904,889,088BergerDec. 26, 19894,562,796EickmannJan. 7, 19863,526,216HenvauxSep. 1, 19704,077,382GentileMar. 7, 19781,135,719RitterApr. 13, 1915These known devices are designed to present an aperture or recessed area along a shaft to the top or inside of the cylinder of an internal combustion engine at a desired moment in the combustion or exhaust cycle. These apertures or recessed areas in the shaft are used as passages for intake and exhaust gasses during the cycle of the engine. It is important to note that while the majority of the discussion provided herein will focus on internal combustion engines, it is contemplated that the principles taught herein may also be applicable to expansion engines, such as steam engines.
U.S. Pat. No. 5,249,553 to Guiod is illustrative of the approach taken by many designers of rotary valve systems. The Guiod device teaches the use of a shaft with indents that are designed to provide “unrestricted and direct” flow of air/fuel into the combustion chamber of the engine. Furthermore, the Guiod device asserts that the indents are designed to assist the rotating shafts in forcing the exhaust into the exhaust manifold and in forcing the air/fuel mixture into the combustion chamber. Unfortunately, how the Guiod indents assist the rotating shafts in forcing gasses into the exhaust manifold or the combustion chamber is not explained in the Guiod specification.
Still further, the “unrestricted and direct” approach of Guiod suggests the absence or very limited interaction between the indents and the flow of gas mixtures into and out of the combustion chamber. Accordingly, the lack of contact between the structure of the rotating shafts of Guiod and the flow of these gasses provides little insight into how the energy contained in this flow can be harnessed. Still further, it is well known that the exhaust gasses in particular are still expanding as they flow out of the combustion chamber, and thus there remains a need for a system that allows the harnessing of the energy being released through the expansion of these gasses.
One of the purposes for using rotary valve systems is the increase in efficiency that appears to be possible with the rotary valve versus the use of poppet type valves. Poppet type valve systems require the use of energy to overcome the springs that hold the valves in a closed position. Furthermore, poppet valves provide a great deal of resistance to the flow of gasses into and out of the combustion chamber. Still further, poppet valve systems use a reciprocating motion, which inevitably results in noise and vibration.
Accordingly, a review of known valve systems for piston engines indicates that there is a need for a rotary valve system that provides the advantages of efficient low flow restriction of rotary valves, and that does so with the use of few moving parts.
There remains a need for a rotary valve system that can remain dimensionally stable in applications that involve high temperature gasses, such as internal combustion engines.
The beneficial use of ceramic materials for both the valve shaft and the cylinder head minimizes thermal expansion during normal and high demand operating conditions. Additionally, ceramic material minimizes the heat transfer between the hot exhaust gasses and associated components and the cooler fuel/air intake mixture and associated components. Furthermore, the inherent property of ceramics makes for more options to attain gas tight seals.
Still further, there remains a need for a valve system that harnesses the energy associated with the flow of gasses out of the piston engine, and thus improving the efficiency of the overall system. This is accomplished by where the curvature of the valve shaft exhaust recessed area forces the energy from exhaust gasses to pass through the valve shaft at a right angle from the combustion chamber which exerts an opposite reaction on the valve shaft in a manner that pushes the recessed area to rotate the valve shaft in the opposite direction of the flow of the exhaust gasses.